The present invention relates to a management of virtual servers that operate on a physical server.
In an information system, there periodically occurs operation for changing a configuration of the physical server such as component replacement associated with version update of software or a failure of hardware, or added resources for performance enhancement. In general, when the configuration is changed, there is a need to reboot the physical server for the purpose of allowing software such as an OS or a hypervisor that operates on the physical server to correctly recognize the configuration change. For that reason, the system stops and is unavailable while the configuration change is being conducted.
In order to reduce a downtime in this situation, the physical server is virtualized, and the virtual server is migrated to another physical server by a migration function. Specifically, all of virtual servers on a first physical server are migrated to a second physical server (virtual server evacuation), the configuration changes of the first physical server and the reboot are conducted (configuration change), and the virtual servers are again migrated to the first physical server, and returned to an original state (virtual server reverse migration). If a live migration function that enables the virtual servers to be migrated with no shutdown is used during migration, the system can be changed in the configuration with no shutdown.
If the configuration change of the physical server is necessary, a system administrator makes a migration plan in advance for the purpose of conducting the configuration change of the physical server and the migration of the virtual servers associated with the configuration change without any problem. The migration plan includes physical servers which are a source and a designation of the virtual server, a time for executing the migration, the contents of the configuration change, and a required time for the configuration change.
One of important elements to be considered in the migration plan is a compatibility of the virtual server operation in the source and destination physical servers. For example, if an instruction set of a processor is different between the source physical server and the destination physical server, the virtual server cannot operate on the destination physical server, and the migration fails. In general, management software of the virtual server is installed with a compatibility check function for preventing such a situation. The compatibility check function collects the respective configuration information and load information of the source physical server and the destination physical server, and compares those information with each other to confirm that the configurations of those physical servers match each other, the operation of the virtual server is not effected by a difference in the configuration between those physical servers, or the destination physical server has resources sufficient to operate the virtual server.
The system administrator can confirm whether the virtual server can be migrated, or not, with reference to the check results of the compatibility by the management software. Then, the check results can be used to determine the destination of the virtual server, and make the migration plan.